Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, and the description is consistent with them. It adds concrete behavioral detail beyond annotations: a 16384-byte input cap, a max of 3 offers, truncation/warning inspection, and no paid fallback. Missing only auth/rate-limit context, which is minor for a free local tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the key qualifier ('FREE, no key') then the operation and constraints. Slight redundancy between 'At most 3 offers' and 'maxOffers defaults to 3', but overall dense and earn-its-place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Output schema exists so return format needn't be explained, and the description hints at truncation/warnings for inspection. Limits, fallback policy, and the larger-input alternative are all covered; only baseUrl semantics remain unaddressed.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It explains the html size cap (16384 UTF-8 bytes) and maxOffers (defaults to 3, capped at 3), but baseUrl is never mentioned and gets no semantic meaning anywhere.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Extract declared Product/Offer JSON-LD from supplied HTML only') with clear scope boundaries. The 'only' and 'no page fetch' phrasing distinguishes it from sibling extractors like commerce_offer_extract.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly names the alternative for larger inputs ('Larger HTML uses the free commerce_offer_extract full tool within its limits') and states what it does not do (no fetch, no JS, no live-price, no orders, no paid fallback). An agent can route correctly.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.